Integrated instrument assembly for compressors

ABSTRACT

An integrated instrument assembly for compressors, having a pressure switch and a pressure reducer connected to each other by a pneumatic circuit, is connectable to a compressor having a compressed-air tank communicating with the pneumatic circuit; the pressure switch and pressure reducer being supported on a supporting member having the pneumatic circuit.

TECHNICAL FIELD

[0001] The present invention relates to an integrated instrument assembly for compressors.

BACKGROUND OF THE INVENTION

[0002] As is known, a compressor is equipped with control and/or safety devices, such as a pressure switch—for cutting off electric power supply to the compressor when a given pressure is reached in the tank—and a pressure reducer.

[0003] Such devices are normally supplied separately and installed on the compressor by the user.

[0004] Such a system is obviously an inconvenience to the user, who must purchase and personally assemble the devices by connecting them to each other by means of fittings and/or installing them on the compressor. Moreover, assembly as described above calls for frequent inspection and maintenance of the fitting seals between the various devices.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide an integrated instrument assembly for compressors, designed to eliminate the aforementioned drawbacks.

[0006] According to the present invention, there is provided an integrated instrument assembly for compressors, comprising a pressure switch and a pressure reducer connected to each other by a pneumatic circuit; the instrument assembly being connectable to a compressor comprising a compressed-air tank communicating with said pneumatic circuit; and the instrument assembly being characterized by comprising a supporting member for supporting said pressure switch and said pressure reducer and having said pneumatic circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

[0008]FIG. 1 shows a view in perspective of a compressor equipped with an integrated instrument assembly in accordance with a preferred embodiment of the present invention;

[0009]FIG. 2 shows a front view of the FIG. 1 instrument assembly;

[0010]FIG. 3 shows a rear view of the FIG. 2 assembly;

[0011]FIG. 4 shows a partly sectioned view of FIG. 2;

[0012]FIG. 5 shows a partly sectioned side view of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Number 1 in FIG. 1 indicates as a whole a compressor comprising a compressed-air tank 2, a motor 3, and a pump assembly 4.

[0014] Compressor 1 is fitted with an instrument assembly 5 connected to pump assembly 4 by a conduit 6 and to tank 2 by a conduit 7, and which comprises two taps 8 and 9 (FIGS. 1 and 5) for feeding compressed air to respective user devices (not shown).

[0015] As shown more clearly in FIGS. 2 to 5, assembly 5 comprises a pressure switch 10; a pressure reducer 11; a pressure gauge 12 showing the air pressure in tank 2; a pressure gauge 13 connected downstream from pressure reducer 11 and showing the pressure of the air supplied by taps 8 and 9; and a thermal safety device 14 connected by cables, not shown, to motor 3 and to pressure switch 10. In an alternative embodiment not shown, safety device 14 is integrated in pressure switch 10.

[0016] Safety device 14 may comprise a relay or resistor (known and not shown), and provides for sensing the temperature of motor 3 and disabling pressure switch 10 when the temperature of motor 3 exceeds a given threshold value.

[0017] Components 10 to 14 of assembly 5 are all mounted on a supporting plate 15 forming part of assembly 5 and having an internal pneumatic circuit 16 communicating with pressure switch 10, pressure reducer 11, and pressure gauges 12 and 13.

[0018] Circuit 16 comprises an inlet 17 connected to pump assembly 4 by conduit 6; an exhaust conduit 18 connected to pressure switch 10; an inlet/outlet 19 connected to tank 2 by conduit 7; and two outlets 20 and 21 (FIGS. 4 and 5) connectable to respective user devices (not shown) by respective taps 8 and 9.

[0019] Circuit 16 comprises an initial portion 22 communicating with inlet 17 and exhaust conduit 18; an intermediate portion 23 communicating with inlet/outlet 19; and an end portion 24 communicating with outlets 20 and 21.

[0020] Assembly 5 comprises a check valve 25 located along circuit 16, between initial portion 22 and intermediate portion 23; and a known safety valve 26 located along intermediate portion 23, and for connecting intermediate portion 23 with the outside when the pressure exceeds a given maximum value.

[0021] Pressure reducer 11 comprises a piston 27 activated by a spring 28; and a truncated-cone-shaped on-off member 29, which is moved by a spring 30 between a rest position (FIGS. 4 and 5), in which no air is supplied by taps 8 and 9, and member 29 closes an opening 31 between intermediate portion 23 and end portion 24, and a work position (not shown), in which air is supplied by taps 8 and 9, and member 29 is lowered by piston 27 to connect intermediate portion 23 and end portion 24.

[0022] In actual use, compressed air is fed by pump assembly 4 into tank 2, and valve 25 is open to connect initial portion 22 and portion 23 until a given maximum pressure is reached; at which point, pressure switch 10 cuts off electric power supply to motor 3 powering pump assembly 4, and a control device inside pressure switch 10 opens a known valve (not shown) to expel the air in portion 22 along exhaust conduit 18, while valve 25 closes to prevent the compressed air from escaping from tank 2.

[0023] When compressed air is required by the user devices (not shown) tap 8 and/or 9 is/are opened, portion 24 is connected to the outside, thus lowering piston 27, which intercepts one end of member 29, which moves down in opposition to spring 30 to connect portions 23 and 24 and so release the compressed air stored in tank 2.

[0024] Using plate 15 to support components 10-14, 25, 26, 8, 9 is particularly advantageous by permitting fast assembly of the instruments as a whole, and by providing a compact, integrated instrument assembly. Moreover, supporting plate 15 is formed, e.g. cast, in one piece, and forming circuit 16 inside supporting plate 15 itself provides for improved strength, sealing and reliability of assembly 5 as compared with known assembly solutions in which the various component parts are connected by fittings.

[0025] Clearly, changes may be made to the instrument assembly as described and illustrated herein without, however, departing from the scope of the present invention. 

1) An integrated instrument assembly for compressors, comprising a pressure switch (10) and a pressure reducer (11) connected to each other by a pneumatic circuit (16); the instrument assembly (5) being connectable to a compressor (1) comprising a compressed-air tank (2) communicating with said pneumatic circuit (16); and the instrument assembly (5) being characterized by comprising a supporting member (15) for supporting said pressure switch (10) and said pressure reducer (11) and having said pneumatic circuit (16). 2) An instrument assembly as claimed in claim 1, characterized in that said supporting member (15) comprises a plate (15) in which said pneumatic circuit (16) is formed. 3) An instrument assembly as claimed in claim 1, wherein said instrument assembly (5) is connectable to a motor (3); said instrument assembly (5) comprising, for said motor (3), a safety device (14) carried by said supporting member (15). 4) An instrument assembly as claimed in claim 1, characterized by comprising a first pressure gauge (12) carried by said supporting member (15) and communicating with said pneumatic circuit (16) to indicate the pressure of the air in said tank (2). 5) An instrument assembly as claimed in claim 1, characterized by comprising a second pressure gauge (13) carried by said supporting member (15) and connected, along said pneumatic circuit (16), to said pressure reducer (11) to indicate the regulated pressure of the air to be supplied to the outside. 6) An instrument assembly as claimed in claim 1, wherein said supporting member comprises first valve means (25) for connecting an inlet (17) of said pneumatic circuit (16) to said tank (2). 7) An instrument assembly as claimed in claim 1, wherein said supporting member comprises second valve means (26) for controlling the pressure in said tank (2). 8) An instrument assembly as claimed in claim 1, characterized by comprising at least one air supply tap (8, 9) fitted to said supporting member (15) and communicating with said pneumatic circuit (16). 9) An instrument assembly as claimed in claim 8, characterized in that said pressure reducer (11) comprises third valve means (29) for connecting said supply tap (8, 9) to said tank (2) to supply air to the outside. 10) An instrument assembly as claimed in claim 6, characterized in that said supporting member (15) comprises fourth valve means for connecting said inlet (17) with the outside. 11) An instrument assembly as claimed in claim 1, characterized in that said supporting member (15) is formed in one piece by a casting process. 